Surgical obturator

Abstract

In a surgical obturator for piercing a body wall, comprising a tubular housing that at one end forms an introduction tip with a continuously decreasing diameter, and comprising a blade projecting from the introduction tip for making an incision in the body wall, in order to reduce the risk of injury during piercing of the body wall it is proposed that the introduction tip comprises a central protective cap, which is displaceable in longitudinal direction relative to the introduction tip between an advanced inoperative position and a retracted working position, that the blade in the housing is displaceable in longitudinal direction between an advanced cutting position and a retracted protected position, that disposed in the housing is a retraction device that displaces the blade from the cutting position into the protected position, and that the retraction device may be activated by a displacement of the protective cap from the working position into the inoperative position.

1. Surgical obturator for piercing a body wall, comprising:
 a tubular housing that at one end forms an introduction tip with a continuously decreasing diameter, 
 a blade projecting from the introduction tip for making an incision in the body wall, 
 a blade carrier which carries the blade, the blade carrier being mounted in a longitudinally displaceable manner in the housing, 
 the introduction tip comprising two portions, a proximal portion, which is part of the housing, and a central protective cap, which is displaceable in a longitudinal direction relative to the housing between an advanced inoperative position and a retracted working position, 
 a retraction device disposed in the housing which comprises:
 a first spring for displacing the blade carrier in the longitudinal direction from an advanced cutting position into a retracted protected position, and 
 a catch, which during advancement of the blade carrier locks the blade carrier in the advanced cutting position, 
 
 the retraction device being activated by a displacement of the protective cap from the working position into the inoperative position, 
 wherein:
 the outer surface of the protective cap in the retracted working position merges continuously into the outer surface of the proximal portion, 
 in the advanced inoperative position a step is formed between the protective cap and the proximal portion of the introduction tip, 
 the blade in the cutting position projects in a region of the retracted protective cap and in a distal region of the proximal portion from a contour of the protective cap and a contour of the distal region of the proximal portion, and 
 the protective cap during the displacement from the working position into the inoperative position releases the catch and triggers the displacement of the blade carrier into the retracted position. 
 
 
     
     
       2. Surgical obturator according to  claim 1 , wherein the blade in the protected position is retracted to such an extent that it no longer projects from the protective cap in the working position of the protective cap. 
     
     
       3. Surgical obturator according to  claim 1 , wherein the protective cap is acted upon by a second spring that displaces the protective cap from the working position into the inoperative position. 
     
     
       4. Surgical obturator according to  claim 1 , wherein the blade in the cutting position does not project from the contour of the proximal portion of the introduction tip in a proximal end region of the proximal portion. 
     
     
       5. Surgical obturator according to  claim 1 , wherein the introduction tip is of a truncated-cone-shaped configuration and has a rounded tip. 
     
     
       6. Surgical obturator according to  claim 1 , wherein the blade carrier carries a gripping element for displacing the blade carrier into the advanced cutting position. 
     
     
       7. Surgical obturator according to  claim 1 , wherein the protective cap in the working position displaces a locking element into a position fixing the catch in a detent position and during advancing into the inoperative position removes the locking element from the detent position. 
     
     
       8. Surgical obturator according to  claim 7 , wherein:
 the catch is held by means of a blocking member in a position fixing the catch in the detent position, and 
 the protective cap in the working position removes the blocking member from the catch and at the same time displaces the locking element into the position fixing the catch, so that the catch remains continuously in its detent position. 
 
     
     
       9. Surgical obturator according to  claim 8 , wherein the blocking member is mounted on the blade carrier. 
     
     
       10. Surgical obturator according to  claim 9 , wherein the blocking member is mounted displaceably on the blade carrier. 
     
     
       11. Surgical obturator according to  claim 10 , wherein the blocking member is a sliding ring that surrounds the blade carrier and is freely displaceable between two end positions. 
     
     
       12. Surgical obturator according to  claim 1 , wherein the catch is a spring-loaded pivotal lever. 
     
     
       13. Surgical obturator according to  claim 1 , wherein the catch and the blade carrier have sliding faces, which, when the catch is not fixed in a detent position and the blade carrier is being pushed back, slide along one another and in so doing move the catch into a release position. 
     
     
       14. Surgical obturator according to  claim 1 , wherein the blade has a helical-line-shaped cutting edge. 
     
     
       15. Surgical obturator according to  claim 4 , wherein the blade has a helical-line-shaped cutting edge. 
     
     
       16. Surgical obturator according to  claim 5 , wherein the blade has a helical-line-shaped cutting edge. 
     
     
       17. Surgical obturator according to  claim 1 , wherein the blade is integrally formed with the blade carrier.